A number of components, such as blades utilised in gas turbine engines, are initially formed in a rough or preformed state and then subsequently processed through additional forming processes such as hot creep forming or superplastic deformation to nearer a final shape as required. FIGS. 1 to 6 of the attached drawings illustrate a typical prior art forming process in which a die former 100 is utilised. The die former 100 comprises a lower die 1 and an upper die combination formed by die parts 2, 3. As illustrated in FIG. 1 a component in the form of a twisted blade preform 4 is placed within the die former 100 between the lower die 1 and upper die 2, 3. Generally, the lower die 1 is static while the upper die 2, 3 is forced under an appropriate load pressure vertically downward towards the lower die 1 such that the mould parts 101, which are typically recesses in the die parts 1, 2, 3 (only shown in lower die 1), are associated to further form the component 4. As will be described later the component 4 and therefore the die parts 1, 2 and 3 are at elevated temperatures in order to provide the hot forming process as required. The forming process may include inducing a twist in a component by the opposed shape of the die parts 1, 2, 3 as they are forced together.
In terms of the method of operation the component 4 is placed in the lower die 1 and typically such that a root part 102 of the component 4 is in position so that an end face 21 engages a stop 11 (which may be referred to as a reciprocal face 11) in a root stop 103 of the die former 100. Furthermore, a trailing edge face 20 of the component 4 engages a stop 10 (which may be referred to as a reciprocal edge face 10) within the die former 100 about a periphery 50 of the mould portion 101.
In the embodiment illustrated the die parts 2, 3 are respectively brought down forcefully and vertically towards the lower die 1. In such circumstances initially the root portion 102 of the component 4 will be held and formed. This will be achieved through the die part 3, as indicated, being forcefully moved down to engage the root part 102 to allow shaping and forming under heat and pressure. The force applied by the die part 3 will cause forming of the root part 102 into its desired, fully formed, final state. FIG. 3 indicates the position of the die part 3 during the forming process while FIG. 4 illustrates the component in position with the die part 3 for root formation removed for clarity.
Once located and secured through the die part 3 and the root portion 102 of the component 4, a further upper die part 2 is brought down forcefully and vertically until a tip or blade portion of the component 4 is fully formed. Thus, as illustrated in FIG. 5 the second die part 2 is adjacent to the first die part 3 and as indicated within the mould parts of the die former 100, shaping and forming of the component 4 achieved. FIG. 6 illustrates the component in its fully completed and formed state presented upon the lower die part 1, with other die parts 2, 3 removed for clarity.
It will be appreciated that the objective of a forming process is to fully form a component, such as a turbine blade, from a rough formed shape into the desired shape typically at high temperature, generally 600° C. to 700° C. The process, as indicated, is typically two stage with an initial first die part 3 brought down followed by a second die part 2. The initial rough formed shape will clearly not be in its final form, and may not fit accurately into the die former, either the lower die 1 or the mould parts of the die former; particularly if a twist is to be formed or extended in the component. In such circumstances upon loading the component 4, an operator is required to adjust, typically using long rigid bars, the position of the component 4 in the mould parts to ensure that the component remains against the stops 10, 11 in the mould parts. Unfortunately, as the die part 3 is typically brought down the initial misshaping of the component dislodges the component from its initial position. Therefore, when the die part 3 is fully closed, a tip of a blade (as an example of a component) may be in a poor position relative to the stops 10, 11. When the die part 2 is fully closed, parts of the component 4 can be positioned such that the die parts 2, 3 must be re-opened and the component repositioned before the dies 2, 3 are re-closed again for forming, in an attempt to improve blade tip position and the overall forming process itself. Such inaccuracies create processing problems as well as potential difficulties with final formed component shape accuracy.